NOFX

Just testing a few items due to a 21mpg '98 D16Y8.

Can I get some opinions on the following information, please?

Some wire color information might seem off as this is in another vehicle ('88 CRX with P28).

MAP RED/YEL to - is 5.03v
MAP YEL/RED to GRN/WHT is 4.99v
MAP WHT to GRN/WHT is 4.64v

With engine running:
MAP middle wire:
-0.02 at idle

TPS YEL/WHT to GRN/WHT is 4.98v
TPS YEL/WHT to - is 5.02v

With engine running:
TPS middle wire:
0.47 at idle (700rpm or so)
0.50 at 1000rpm
0.55 at 1500rpm
0.60 at 2000rpm
0.66 at 2500rpm
0.70 at 3000rpm
0.74 at 3500rpm


For wire color information, from the '88 CRX ETM:

MAP (C217):
*WHT goes to ECU (Input)
*GRN/WHT (-) goes to ECU (Input)
*YEL/RED (+) goes to ECU (Input)

TPS (C168):
*YEL/WHT goes to EGR Valve Lift Sensor
*RED/BLU goes to ECU (Input)
*GRN/WHT goes to a splice (S103) that is shared with the IAT, Coolant Temp (TW), EGR Valve Lift Sensor, and another splice (S443)

NOFX

Bump

Lizardslap

Ok I got a few Questions for you any cels being thrown, Are your fuel injectors the correct Sized for that moter/ecu

and as for your tps you dont need the car running and Idk what to tell you with that information it should go from .48 at closed throttle to exactly 4.5v at wide open

and for adjusting https://honda-tech.com/forums/tech-misc-15/diy-how-calibrating-voltage-your-tps-sensor-2947986/

NOFX

More concerned with the MAP. Output tested bad. Going to wire in the other MAP I have.

I'm not sure what you see wrong with the TPS testing. Got the reference voltage tests from the Honda FSM and the TPS is a potentiometer so I tested at different rpm.

Former User

Auto or manual transmission?

NOFX

Manual transmission. I can't own automatics.

NOFX

Engine was previously running 33mpg in this car btw. I do not expect it to be related to the set-up of the swap, as people keep suggesting (without ever imagining that maybe in two years something could fail or wear out!).

Former User

P28 with D16Y8 chip? Or does the Y8 run perfectly on a D16Z6 ECU?

I think you meant Yel/Red here^. if so, looks fine.

Voltage? What color is the middle wire?

Looks fine.

Okay

Nope. This wire get 5 reference volts from the ECU. The TPS has nothing to do with the EGR valve.

Yes

NOFX

Chipped P28. Timing is different between the D16Z6 (which is the engine that matches to the P28) and the D16Y8.
Yes. Typo.
Middle wire is GRN/WHT.

MAP is:
1 WHT output
2 GRN/WHT -
3 YEL/RED +

WHT to negative at idle 0.98. WHT to negative key on position engine off 0.01.
I could have gotten crossed in the books.

TPS is:
1 YEL/WHT +
2 RED/BLU output
3 GRN/WHT -

Former User

All sensor information looks fine.

Last ignition system tune up? Ignition timing set to spec? Fuel pressure fine? Any stuck open injectors? Engine running cold? Brakes dragging? Low tire pressure? Combination of latter?

NOFX

New plugs. Old plugs looked fine and uniform coming out. Wires replaced two years ago iirc. Timing dead on. Engine runs at temp.

Will have to check fuel pressure. How could I tell an injector is stuck open?

Former User

This^ probably means no injectors are stuck open.

The plug wires are worth considering.

Cap, rotor, distributor? Any CEL codes?

^With and without the FPR vacuum hose connected.

Exhaust leak near O2 sensor?

NOFX

I figured that about the plugs, which was why I mentioned it.

Anyway to test consistent reliability of the current wires?

I believe I did the cap and rotor recently. With so many cars it gets confusing. Absolutely zero codes for the moment.

On the topic of CELs though, I realized several weeks ago that though I did not have a visible CEL on in the dash, when I jumped the wires to read any CELs, I had a "soft code" for the VTEC Solenoid Valve. I cleared it, gassed up twice since then and have repeatedly checked for CELs again and have found none. No idea why it came on to begin with.

I'll have to rent a tester for the fuel pressure.

I believe I have (for the entire life of the swap) an exhaust leak between the header and b-pipe, but there is no leak near the single O2 sensor in the Civic exhaust.

Former User

Ohm test and check for spark arcing in a dark place at night.

Well, better check or replace them. Also consider Ohm testing the coil and having AZ test the ICM.

I think you mean the A-pipe. Best to fix the leak and check for a cracked header.

NOFX

I'll test it all asap.

B-pipe. A-pipe went out with the HF exhaust manifold. I'm using the Civic EX exhaust manifold now, with the CRX b-pipe next, and the CRX muffler following that.

So the leak is under the passenger compartment of the vehicle.

http://www.hondapartsdeals.com/hpa_p...onGroupID=5986

Telecatster

MPG drop seems to be fairly common in a lot (according to many posts here) of older civics. My guess and assumption is a weakened o2 sensor. Unfortunately, it is an expensive part to guess at. May try Scotty Kilmer's (youtube) o2 sensor cleaning method or this way (at your own risk).

canadaek

it is much easier to test the tps with the key on engine off . Is your o2 sensor located in the rear of the manifold ? another sensor that can greatly effect fuel economy is the Ect sensor .

Telecatster

Too right: https://honda-tech.com/forums/acura-integra-6/coolant-temp-sensor-causing-bad-gas-mileage-1831811/

NOFX

So I rented a fuel pressure tester only to discover it (and the entire store) didn't have an adapter small enough for my car.

I really don't think I have a fuel delivery issue though. The car doesn't have much of a runability problem at all. Maybe a little bit of an occasional rough idle and a bit of a hiccup when starting from a stop.

My setup has a single 4 wire primary O2 sensor. No code is thrown unless the sensor is unplugged. Tests of the sensor show a good sensor. I also tested a brand new O2 sensor and got similar results.

My O2 sensor is a standard primary O2 sensor on my 1998 Civic EX exhaust manifold.

TPS is:
1 YEL/WHT +
2 RED/BLU output
3 GRN/WHT -

TPS output is 0.52 KOEO and 0.46 at idle. Just went out and checked.

HF MAP: 0.98 idling. 0.01 KOEO.

Y8 MAP: 1.01 idling. 2.96 KOEO.

HF MAP reads approximately the same now... but the engine bay is to temp now and it's been dry all day. Last few days when I tested the bay was cold and weather had been very wet.

Upon extending wires and plugging in the Y8 MAP, the car seemed to idle smoother and take off smoother.

Gassed up on my way home from work. 21.9mpg on 53 miles.

NOFX

To clarify the order of things, I did the 5v reference tests a few days ago. Before work today I extended the MAP wiring and plugged in the Y8 MAP. Drove to work. Got off work, filled the tank again, drove some, tested the Y8 MAP output, tested the HF MAP output.

O2 sensor was something I tested extensively and repeatedly weeks ago.

NOFX

Gotten an occasional hunting idle a few times since the MAP swap. It only seems to occur after the car has been driven and parked at temp. And it doesn't always happen.